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Observations about couplers

wehtam721

New member
Hello everyone,

As I've been playing lately, I've noticed two things about how couplers are working that seem to me to be less than favorable. I'm not sure how feasible a fix to either issue would be, but I thought it was worth mentioning. I'm attaching two videos to help demonstrate what I'm trying to explain here.

1. I'm guessing that the algorithm for recalling stops and couplers from a general/divisional is really just very rapidly changing the state of the stops/couplers one at a time. Knowing the little that I do about computer programming, running a loop of sorts to take care of this would be my first thought. At the present, it seems that stop changes happen first, then couplers.

In the video you can see the complications of this. When a coupler is engaged, you can hear a "chirp" of stops/pitches that shouldn't actually play because the stops have been switched on before the related coupler was switched off. In the video, I give two examples. First, switching between a flute which is played at 8' and 4' pitch (using a 4' coupler) and a trumpet without the coupler. You can hear the trumpet play really quickly at 4' pitch because the coupler hasn't turned off yet. The second example shows how it could affect percussion stops. The glockenspiel in the choir of my organ plays on the great because (again) it is switched on before the choir to great 8' coupler is switched off. Playing subsequent notes shows that the glockenspiel is only triggered in that instant when the switch takes place.

I'm not sure that there's a good fix for this because simply switching the order so that couplers changed state first, followed by stops would cause a similar problem. I'm guessing that this problem is worse on very large organs because there are more stops to switch on and off before the algorithm gets to the couplers. Perhaps couplers should be triggered immediately before/after their respective divisions which might minimize the effect? Either way, this is not an earth shattering problem because it's only noticeable under certain circumstances, just something that I've run across.


2. The second thing I've noticed is that manuals which are coupled do not respond to low velocity key presses. Most of the time this is not a problem, but I can hear it happen from time to time while I'm playing. In the video, I have one division with stops drawn coupled to the great and no stops drawn on the great at all. You can see that I am pressing keys down on the great (because they show on the GrandOrgue display in red) but the corresponding keys on the coupled manual do not play even though I would expect them to. This happens when I very delicately press the keys down on my keyboards which are velocity sensitive. Just after demonstrating this, I play with normal force, and the coupler functions exactly as expected and you see the keys "depress" on both manuals on the screen. It seems like something in the code might be causing coupled manuals to not respond to the full range of velocities by default. Each manual responds to even the most delicate of keypresses on its home keyboard, even when couplers are engaged. The issue only takes place on the manuals that other divisions are coupled to.


Sorry that this is such a lengthy post. I was trying to be clear about what I was observing. Hopefully the videos help to show what I'm describing, but if anything is still unclear, please let me know. If there's any additional information that I can provide about what I've noticed, let me know and I'll be happy to run some tests and get back to everyone.

Take care,
Matt
 

Attachments

  • 1.mp4
    1.3 MB · Views: 7
  • 2.mp4
    1.8 MB · Views: 4

e9925248

New member
Add 1)
On a real organ, not everything is change at the same moment. The difference is, that very short activations are too short to influnce the sound, because pipes need more time to start sounding.

Did you try the MEL/BAS couplers? It also suffers from the fact, that sort activations produce an auditable sound.
In my option, the fade out of such sort activations of non-percussive samples need to be changed.

Add 2)
In the current code, passing over a coupler looses one velocity unit. So are you really managing playing with a velocity of 1?
 

wehtam721

New member
1)
I have not tested this with MEL/BAS couplers as of yet, but it makes sense that the same issue would occur. You've hit the nail on the head, I think, in your explanation. I know that on a real pipe instrument not all of the changes happen at the same moment but, as you said, it happens sufficiently fast enough that the pipes don't have time to speak. In my opinion, it would be nice if GrandOrgue behaved in the same way.

2)
Am I playing with velocity 1? So it would seem...or at least that's the data that GrandOrgue is receiving. I think it's actually much more likely that my keyboards are sending less than perfect velocity information to the computer. In building my organ, I've had to look closely at how the keyboards work and it seems unlikely to me that the keyboards that I have would actually be able to detect 127 different levels of velocity. They just don't seem that precise. I've also read online that other people having the same keyboards that I do have had some trouble getting velocity values in the 100s. Perhaps the keyboards are only sensing in ranges and sending the lowest velocity value in the range? Rather than me actually playing at a velocity of 1, what seems more likely to me is that perhaps the keyboards aren't that sensitive and they're sending a value of 1 for any very soft keypress.

I can easily make it happen when I'm trying to do so. I would never be able to actually play a piece of music like this though. When actually playing, I realistically only notice this once in a great while when a note is re-articulated before the key has returned to the neutral position (or some similar situation) which cause the velocity reading to be less than it might otherwise be.
 

L.Palo

New member
I can confirm that it's very easy to hit a velocity 1 with the M-Audio keystation 61es too. Also it's very difficult to have a velocity value greater than 100.

Would it be possible to avoid loss of velocity in the coupling mechanism?

Kind regards

Lars P
 

wehtam721

New member
I thought I had mentioned this, but as I look more closely at my post it seems as though I did not. I am also using the M-Audio keystation 61es. That explains why Lars and I have the same experience. These are the only MIDI keyboards that I have (and that I have ever had) so I don't know what the experience would be like on another brand/model.

Matt
 

wehtam721

New member
An additional thing I've noticed (as I continue to explore different possibilities with GrandOrgue) is that couplers only allow for a maximum key shift of 24. I'm wondering if this could be increased without much hassle. I know that it would be extremely odd to see something beyond the range of a super octave coupler, but it would be nice if you have keyboards which don't all send the same midi note messages (which is the case that I'm in).

I used an M-Audio Keystation 88es to wire up my pedal board for MIDI and the first note on the 88es sends MIDI note 21 (whereas my manuals, as you'd expect, send note 36 as their lowest note). I've set the ODF so that the pedalboard plays the correct notes and use a key shift of 15 for 8' couplers from manuals to pedals. When I went to add some pedal couplers at 4' pitch, however, I ran into a problem. I would need a key shift of 27 (15 to account for the difference in MIDI messages being sent and 12 for the octave coupler) with my setup, but the highest value allowable is 24.

If there's a way to work around this problem which already exists, please let me know what that would be. Otherwise, would it be possible to increase the allowable range for the couplers? I recognize that this situation would be an unlikely one for somebody to come across, but it's possible if people are using a variety of MIDI hardware.

I hope that everyone has had a good holiday season and that you all have a great upcoming new year as well!

All my best,
Matt
 

L.Palo

New member
Hi!

Have you tried transposing that manual (pedal) individually instead?

Right click on the manual (pedal) and change the transposition to take care of the offset (maybe 15 then). If this works for you then leave the odf setup as it ideally should have been.

Kind regards

Lars P
 

wehtam721

New member
Lars,

I just tried the transposition and it worked like a charm! That's exactly what I've been looking for to solve the problem. I can't believe I hadn't noticed that setting before in all the times I've looked at those manual MIDI settings windows.

Thanks for the suggestion!,
Matt
 
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